QGIS Python ImportError: No module named builtins

Question

When I am executing a python script for doing a geoprocessing task using QGIS Desktop 3.8.3 (executed using a windows .bat file), I am getting an import error.

from builtins import zip
ImportError: No module named builtins 

In C:\OSGeo4W64\apps\, I can find folders namely Python27 and Python37. I have installed Python 3.7 version before installing OSGeo4W64.

The .bat file (from which I am executing this .py file) is :

@echo off
call C:\OSGeo4W64\bin\o4w_env.bat
call C:\OSGeo4W64\bin\qt5_env.bat
call C:\OSGeo4W64\bin\py3_env.bat
REM Change OSGEO4W_ROOT to point to the base install folder
set QGIS_PREFIX_PATH=C:\OSGeo4W64\apps\qgis
REM Gdal Setup
set GDAL_DATA=C:\OSGeo4W64\share\gdal\
REM Python Setup
set PATH=C:\OSGeo4W64\bin;C:\OSGeo4W64\apps\qgis\bin;%PATH%
SET PYTHONHOME=C:\OSGeo4W64\apps\Python27
set PYTHONPATH=C:\OSGeo4W64\apps\qgis\python;%PYTHONPATH%

REM Launch python job
python C:/V/V.py
pause

The .py file starts like :

from osgeo import ogr, gdal
from gdalconst import *
from qgis.core import *
import qgis.utils, sys
from qgis.gui import *
from PyQt5.QtGui import *
from PyQt5.QtCore import Qt
from PyQt5.QtCore import QFileInfo
app = QApplication([])
QgsApplication.setPrefixPath("C:/OSGeo4W64/apps/qgis", True)
QgsApplication.initQgis()
sys.path.append('C:/OSGeo4W64/apps/qgis/python/plugins')
import processing
from processing.core.Processing import Processing
Processing.initialize()
from processing.tools import * 

In Environment Variables, in User variables,

Path : C:\Users\sreeraj\AppData\Local\Programs\Python\Python37\Scripts\, C:\Users\sreeraj\AppData\Local\Programs\Python\Python37\
OSGEO4W_ROOT : C:\OSGeo4W64 

And in System variables,

Path : C:\Users\sreeraj\AppData\Local\Programs\Python\Python37\Scripts\, C:\Users\sreeraj\AppData\Local\Programs\Python\Python37\ 

Inside python-core.bat in C:\OSGeo4W64\etc\ini\, I can find

SET PYTHONHOME=%OSGEO4W_ROOT%\apps\Python37
PATH %OSGEO4W_ROOT%\apps\Python37\Scripts;%PATH% 

But I can't find any variables like PYTHONPATH or PYTHONHOME in Environment Variables (I don't know whether this information will be useful for solving this importerror or not.)

How can I solve this ImportError : No module named builtins ?

Answer 1

builtins module does not exists in Python 2 (it's called __builtin__). So probably you are using the wrong Python interpreter.

Just to be sure try to print sys.version_info to know which version are you using, and sys.executable to get the absolute path to the interpreter.

I have no experience on Windows but probably you can use the Python 3.7 interpreter changing:

SET PYTHONHOME=C:\OSGeo4W64\apps\Python27

with

SET PYTHONHOME=C:\OSGeo4W64\apps\Python37

Answer 2

This is because newer versions of PsychoPy support both Python 2.7 and 3. The future package is used to ensure the code runs on both platforms. From command prompt run the following:

  pip install future

or via conda command prompt:

  conda install future